Berdly is sort a dick sometimes, he's that dude with an attitude who usually thinks he's better than most people. But he's been shown to have a genuine side to him. I think he'd sound pretty nerdy, but also pretty cocky as well if that makes sense.

Personality (from Wiki)

Berdly is sarcastic and arrogant. If spoken to in class, he chastises Kris for being late and says he is already partnered with the second smartest student, implying that he is the smartest. He vehemently does not want to work with Kris on the class's group project, disparaging Kris's skills and arguing that he actually wants to get an A grade. He argues vehemently when his partner, Noelle, asks Alphys for permission to let Kris join them and make a group of three.